Experimental And Simulation Study On CDPF Regeneration Timing

The combined use of DOC+CDPF is one of the development trends of diesel exhaust particulate post-processors technology,not only reduces CO,HC and particulate levels,but also enables continuous regeneration of CDPF.Reliable regeneration is a key technology of CDPF.Accurate prediction of carbon content is an important prerequisite for safe and reliable active regeneration of CDPF.Reasonable inlet conditio ns are the means to ensure safe and reliable regeneration.In order to study the capture characteristics of CDPF,to find the method of determining the regeneration time,and to find the optimal inlet conditions for the regeneration of CDPF,this paper matched a DOC+CDPF on a diesel engine with a displacement of 8.4L.The key technologies su ch as CDPF regeneration time was studied by combining test and simulation.The test results show that when the flow rate of the exhaust gas is constant,the carbon content of the filter is linear with the pressure drop.Based on pressure drop of filter,This paper proposes a carbon load calculation method for CDPF.The actual carbon content of the current state CDPF is calculated by taking the pressure drop,the safe soot limit and the exhaust gas flow as the main parameters.The method was found to have high accuracy by verification.Based on the above findings,this paper proposes a method for judging the carbon loading of the filter as the timing of regeneration.The me thod is simple,reliable,easy to implement and has a wider application range.The simulation results of CDPF regeneration show that when the inlet temperature is lower than 550?,the internal maximum temperature of CDPF decreases with the increase of inlet flow rate and the maximum drop is 17.97%.When the inlet temperature is higher than 590?,the internal maximum temperature rises slightly.The simulation analysis of the regeneration time shows that increasing the inlet flow rate at the same inlet temperature can shorten the regeneration time of CDPF,increasing the inlet temperature under the same inlet flow rate can effectively shorten the regeneration time,and the maximum reduction of the regeneration time can reach 86.84%.The simulation study of regenerative energy consumption shows that when the inlet temperature is the same,the energy consumption for CDPF complete regeneration is significantly increases with the increase of the inlet flow rate,and this phenomenon is especially obvious when the inlet temperature is lower than 550?,and the maximum energy consumption can increase by 285.51%.When the inlet flow rate is constant,the energy consumption for CDPF complete regeneration is significantly reduced with the increase of inlet temperature.This phenomenon is especially obvious when the inlet flow rate is high,and the maximum energy consumption can be reduced by 77.07%.Considering the regeneration time and the regeneration energy consumption,this paper divides the inlet condition range into four regions,and determines that the 560-590?inlet temperature and the 0.08-0.125kg/s flow rate as the best economical rapid regen eration inlet condition;the 550-600 ? inlet temperature and the 0.05-0.08kg/s flow rate as the Low-speed economic regeneration conditions;the 560-600? inlet temperature and the 0.125-0.2kg/s flow rate as the rapid vehicle regeneration conditions;The regeneration time and economy of the medium to low exhaust temperature zone are not advantageous,so CDPF's regeneration should be avoided in this area.